I have basic Civ 4. I'm not sure which version, but a quick look at the readme file says V109?

Anyway, my problem is this. I cant play some of the scenarios that come with the game. I can play the Earth scenarios, but not the American Revolution one or the Greek World one. When I try to play the American Revolution one it tells me this: "This scenario requires the "Mods\American Revolution\" mod. The game must restart to load this mod."

And when I restart the game, it still doesnt work. I dont know if the problem is because I have Windows Vista as my OS or what? I'm reluctant to download a patch because I see that a lot of people have problems with running the game on Vista and since everything else is working fine for me, I dont want to muck anything up. Does anybody know the solution to this problem?

Can anybody help me, please?

first try applying the most recent patch. You can find it here (http://forums.civfanatics.com/downloads.php?do=file&id=6183) you will also need to install the newest DirectX9c version from microsoft, which you can find here (http://www.microsoft.com/downloads/details.aspx?FamilyID=cb7397f3-0949-487b-9247-8fee451bf952&DisplayLang=en). If the problem persists please come back :)

Well, see thats my problem. I'm affraid that if I install the patch that it may not work because I have Vista. I have it working now and I dont want to change anything and make it not work.

the thing is that there are quite a few Vista related problems out there - especially with the earlier versions ;)
Anyway, the fact that the mod does not start at all hints at some sort of install problem, if you want you can open your civilizationIV.ini and set everything that has log in its name to 1. Then try starting a mod and if it does not start post a zip with everything in your my games/sid meier's civilization 4/logs directory here.
Also you can try setting the value for mod in your .ini from 0 to the exact name of the mod that does not start (e.g. American Revolution) and just start civ it should then try to start the mod from the beginning and if this does not start zip the log files again (they are being overwritten everytime you start the game).

Woah lol. Its not that big of a deal. I will just leave it like it is. Thanks a ton though man!

Well I bought Warlords today and it installed the V1.61 Patch, so I will try it out and see how it works! I hope all goes well....I will come back with any problems.